Kicking Up 

 More Than Clams 



Studying the effects of clam kicking on seagrass 



Bij Atlcu Wevis 



mSSSSSi 



BY KATHY HART 



Peterson paints clams for later identification in the laboratory 



he results can be deci- 

 phered from graphs in a sci- 

 entific paper. But the real 

 proof is a grass bed in Back 

 Sound. Either way, the conclusion is 

 the same: clam kicking is harmful to 

 seagrass beds. And anything that ad- 

 versely affects seagrass spells trouble, 

 unproductive trouble. 



As part of a large Sea Grant project 

 to study the biology of the hard clam 

 and the effects of its harvesting 

 methods, researcher Charles "Pete" 

 Peterson sectioned off plots of sea- 

 grass in Back Sound to test the effects 

 of clam kicking. Some of the plots 

 were left untouched and used as con- 

 trols to measure against the effects of 

 raking, light kicking and intense kick- 

 ing in other plots. 



In the raking and light kicking plots, 

 seagrass biomass dropped approxi- 

 mately 25 percent immediately after 

 harvest. But within a year's time, these 

 beds completely recovered. 



In the intensely kicked plots, sea- 

 grass biomass fell by about 65 percent 

 immediately after harvest. The beds 

 did not begin to recover for two years. 

 And four years later, the intensely 

 kicked plots still had 35 percent less 

 seagrass than the control plots. 



Why the concern for a bed of sub- 

 merged grass? Peterson explains: "Sea- 

 grass stimulates productivity. It's part 

 of the detrital food chain. The grasses 

 also function as habitat for small inver- 

 tebrates and other creatures. It pro- 

 vides a surface for the attachment of 

 young scallops, and juvenile clam set- 

 tlement is higher in grass beds. It also 

 affects shrimp production." 



The bottom line? Seagrass is an 

 important part of the estuarine ecosys- 

 tem. It provides food, directly or indi- 

 rectly, refuge and habitat for the small- 



